Retinoid regulated association of transcriptional co-regulators and the polycomb group protein SUZ12 with the retinoic acid response elements of Hoxa1, RARbeta(2), and Cyp26A1 in F9 embryonal carcinoma cells

J Mol Biol. 2007 Sep 14;372(2):298-316. doi: 10.1016/j.jmb.2007.06.079. Epub 2007 Jul 3.


Hox gene expression is activated by all-trans retinoic acid (RA), through binding to retinoic acid receptor-retinoid X receptor (RAR-RXR) heterodimers bound at RA response elements (RAREs) of target genes. The RARs and RXRs each have three isotypes (alpha, beta, and gamma), which are encoded by distinct genes. Hox genes are also repressed by polycomb group proteins (PcG), though how these proteins are targeted is unclear. We used chromatin immunoprecipitation assays to investigate the association of RXRalpha, RARgamma, cofactors, and the PcG protein SUZ12 with the Hoxa1, RARbeta2, and Cyp26A1 RAREs in F9 embryonal carcinoma cells (teratocarcinoma stem cells) during RA treatment. We demonstrate that RARgamma and RXRalpha are associated with RAREs prior to and during RA treatment. pCIP, p300, and RNA polymerase II levels increased at target RAREs upon exposure to RA. Conversely, SUZ12 was found associated with all RAREs studied and these associations were attenuated by treatment with RA. Upon RA removal, SUZ12 re-associated with RAREs. H3ac, H3K4me2, and H3K27me3 marks were simultaneously detected at target loci, indicative of a bivalent domain chromatin structure. During RA mediated differentiation, H3K27me3 levels decreased at target RAREs whereas H3ac and H3K4me2 levels remained constant. These studies provide insight into the dynamics of association of co-regulators with RAREs and demonstrate a novel link between RA signaling and PcG repression.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Acetylation
  • Animals
  • Base Sequence
  • Cell Line, Tumor
  • Cytochrome P-450 Enzyme System / genetics*
  • Gene Expression Regulation / drug effects*
  • Histone Acetyltransferases / metabolism
  • Histones / chemistry
  • Histones / metabolism
  • Homeodomain Proteins / genetics*
  • Kinetics
  • Lysine / metabolism
  • Methylation
  • Molecular Sequence Data
  • Nuclear Receptor Coactivator 3
  • Polycomb-Group Proteins
  • Protein Binding / drug effects
  • RNA Polymerase II / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Receptors, Retinoic Acid / genetics*
  • Receptors, Retinoic Acid / metabolism
  • Repressor Proteins / metabolism*
  • Response Elements / genetics*
  • Retinoic Acid 4-Hydroxylase
  • Retinoid X Receptors / metabolism
  • Trans-Activators / metabolism
  • Transcription Factors / genetics*
  • Transcription, Genetic / drug effects
  • Tretinoin / pharmacology*
  • p300-CBP Transcription Factors / metabolism


  • Histones
  • Homeodomain Proteins
  • Polycomb-Group Proteins
  • RNA, Messenger
  • Receptors, Retinoic Acid
  • Repressor Proteins
  • Retinoid X Receptors
  • Trans-Activators
  • Transcription Factors
  • homeobox A1 protein
  • retinoic acid receptor beta
  • Tretinoin
  • Cytochrome P-450 Enzyme System
  • Retinoic Acid 4-Hydroxylase
  • Histone Acetyltransferases
  • Nuclear Receptor Coactivator 3
  • p300-CBP Transcription Factors
  • RNA Polymerase II
  • Lysine